This weekend's haul

From: A.R. Duell <ard12_at_eng.cam.ac.uk>
Date: Mon Jun 9 22:03:54 1997

> > If it's the same as the XT external floppy connector (and I think it is!),
> > the 34 wires of the standard floppy connector are connected to the
> > 'bottom' (higher numbered) pins on the 37 pin D plug. Pins 1,2,20 are no
> > connection, pin 3 is wire 2, pin 4 is wire 4, pin 5 is wire 6, etc. Pins
> > 21-37 are all grounded.
> >
> > It's a standard DC37 connector, available from any good electronics parts
> > place, I think. You can get solder, PCB mount or IDC versions.
>
> Excellent! Thanks for the info! As I said earlier, I have a use for this
> drive, but I don't really want to modify it. Hopefully I'll be able to
> feed a ribbon cable with the 37-pin D connector on it out of my Amiga's
> Sidecar.

If you have got a standard 34 wire floppy cable (that will link to a
normal PC drive), you can crimp an IDC DC37-S connector on to it (insert
the cable so that pins 1,2,20 have no wires on them), and the plug the
drive in. Apart from drive select and motor run signal problems (the 'PC
twist' is the root of these), it should work fine.


>
> I hope there wouldn't be problems with noise, etc, over lengthy cabling?

Well, at one time floppy cables were properly terminated (a 150 Ohm
resistor pack in the drive furthest from the controller), and could be
quite long. Alas, termination was considered too hard for the average
user, so modern drives have 1k pull-ups (they are in no sense
terminators), and nothing else. They may therefore fail to work on long
cables.

If you are feeling hackish, you might try adding some 150 Ohm termination
resistors to the last drive on the cable (or replacing the 1k ones, which
may well be microscopic SMD ones, alas) and seeing if that helps.

> > > Heh. I couldn't even get mine apart, because of the two six-pointed
> > > screws on the bottom. The screws have a lump in the middle so I can't use
> > > a flat-blade screwdriver as I did when I had a similar problem opening my
> > > Mac 512K.
> >
> > Tamperproof TORX screws. Drivers for them are available from good tool
> > shops in the UK - I have a reasonably complete set to deal with such
> > things...
>
> Well, I haven't seen any around here (Canada) but perhaps I haven't been
> looking hard enough. I also haven't been trying to get the drive open
> because other things have come up.

I did say _good_ tool shops. I know perhaps 4 places in the UK (There are
obviously more) that keep them, and an awful lot that don't.

I've lost count of the number of different 'unscrewing tools' I use - but
it's a rather large number.


--
-tony
ard12_at_eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
Received on Mon Jun 09 1997 - 22:03:54 BST

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